As far as the request, if it is that important to you, I would first see if what you want can be requested as part of online check in. If it can, do so. If not, I would call now and have the request added to your booking. Whichever one of these you have done, once you receive your room number on check in day, you can still request a change if they did not meet your request. They may not be able to meet it, but at least you will have the best chance. There is no advantage to waiting until five days out vs. five months out. In fact, getting the request in as early as possible may help in the event they start playing room Tetris earlier than expected.
The best advice I can give you is to keep your requests as simple as possible. I rarely make any request other than top floor or close transportation, depending on the resort. So far, I have not been disappointed.